Citation
Abstract
This article analyzes proposed systems for Deep Space Network (DSN) microwave antenna holography. Microwave holography, as applied to antennas, is a technique which utilizes the Fourier Transform relation between the complex far-field radiation pattern of an antenna and the complex aperture field distribution to provide a methodology for the analysis and evaluation of antenna performance. Resulting aperture phase and amplitude distribution data are used to precisely characterize various crucial performance parameters, including panel alignment, subreflector position, antenna aperture illumination, directivity at various frequencies, and gravity deformation, Microwave holographic analysis provides diagnostic capacity as well as, perhaps more significantly, a powerful tool for evaluating antenna design specifications and their corresponding theoretical models. Functional requirements, performance, and potential for future technological growth are considered, leading to a description of complete in-house DSN capability for operational “health checks,” evaluations, diagnostics, and performance optimization, as well as a flexible R&D tool for further development of large antennas. Wide-bandwidth, narrowbandwidth, and phase-retrieval systems are analyzed and discussed with respect to three relevant signal sources: a natural radio star, a satellite channel of perhaps telephone or computer data that can be treated as a Gaussian noise source, and a satellite CW beacon. A recommendation based on systems analysis is made to first implement the narrowbandwidth CW system. ft will provide high-resolution and low-resolution holographic maps with high precision suitable for individual panel setting, and function as a flexible R&D engineering tool offering future growth potential, With modest software addition, a wide-bandwidth 1-bit correlator could become part of that system, providing lowresolution maps in the DSN frequency bands that satisfy the requirement for a quick response to operational needs. Since the implementation of 1-bit correlators in the DSN stations is not envisioned before 1994, and since DSN Operations desires a low-cost implementation of quick “health check” diagnostic capabilities as soon as possible, it is recommended that a phase-retrieval-based holography system be developed for that purpose.
Details
- Volume
- 42-96
- Published
- February 15, 1989
- Pages
- 132–157
- File Size
- 1.3 MB